Premix-type burners are used in boilers and other heating applications where combustion air is fed, under pressure, to a plenum chamber. The combustion air enters one or more burners which have inlets that communicate with the plenum chamber and is mixed with fuel, such as natural gas. The mixture is then burned within a combustion chamber forming part of the appliance. The efficiency of this type of appliance is in part determined by the primary air/fuel mixing capability of the burner.
It is desirable to provide a cost effective burner for this type of application which also provides effective primary air/fuel mixing capability.